PHP 5.4.36 Released

mysqli::select_db

mysqli_select_db

(PHP 5)

mysqli::select_db -- mysqli_select_dbSelects the default database for database queries

Description

Oriented object style

bool mysqli::select_db ( string $dbname )

Procedural style

bool mysqli_select_db ( mysqli $link , string $dbname )

Selects the default database to be used when performing queries against the database connection.

Note:

This function should only be used to change the default database for the connection. You can select the default database with 4th parameter in mysqli_connect().

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()

dbname

The database name.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 mysqli::select_db() example

Oriented object style

<?php
$mysqli 
= new mysqli("localhost""my_user""my_password""test");

/* check connection */
if (mysqli_connect_errno()) {
    
printf("Connect failed: %s\n"mysqli_connect_error());
    exit();
}

/* return name of current default database */
if ($result $mysqli->query("SELECT DATABASE()")) {
    
$row $result->fetch_row();
    
printf("Default database is %s.\n"$row[0]);
    
$result->close();
}

/* change db to world db */
$mysqli->select_db("world");

/* return name of current default database */
if ($result $mysqli->query("SELECT DATABASE()")) {
    
$row $result->fetch_row();
    
printf("Default database is %s.\n"$row[0]);
    
$result->close();
}

$mysqli->close();
?>

Procedural style

<?php
$link 
mysqli_connect("localhost""my_user""my_password""test");

/* check connection */
if (mysqli_connect_errno()) {
    
printf("Connect failed: %s\n"mysqli_connect_error());
    exit();
}

/* return name of current default database */
if ($result mysqli_query($link"SELECT DATABASE()")) {
    
$row mysqli_fetch_row($result);
    
printf("Default database is %s.\n"$row[0]);
    
mysqli_free_result($result);
}

/* change db to world db */
mysqli_select_db($link"world");

/* return name of current default database */
if ($result mysqli_query($link"SELECT DATABASE()")) {
    
$row mysqli_fetch_row($result);
    
printf("Default database is %s.\n"$row[0]);
    
mysqli_free_result($result);
}

mysqli_close($link);
?>

The above examples will output:

Default database is test.
Default database is world.

See Also

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User Contributed Notes 2 notes

up
-1
pjasiulewicz at gmail dot com
3 years ago
In some situations its useful to use this function for changing databases in general. We've tested it in production environment and it seams to be faster with switching databases than creating new connections.
up
-2
hwalker1 at btopenworld dot com
11 months ago
Note that in the second example, if the database "world" does not exist, the database selected does not change. You may need to add additional code to ensure that you are connected to the correct database.
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